What are the typical presentation and recommended management of Bell palsy?

Bell's Palsy: Presentation and Management

Clinical Presentation

Bell's palsy presents as acute unilateral facial weakness or paralysis developing over less than 72 hours, with the hallmark feature being forehead involvement that distinguishes it from central causes like stroke. 1

Key Diagnostic Features

• Rapid onset of unilateral facial weakness developing over 24-72 hours, affecting all facial muscles including the forehead 1, 2
• Inability to wrinkle the forehead or raise the eyebrow on the affected side—this forehead involvement is mandatory for diagnosis and differentiates Bell's palsy from stroke, which spares the forehead 1, 3
• Incomplete eye closure (lagophthalmos) causing significant risk of corneal exposure and damage 1
• Oral incompetence with difficulty eating, drinking, and speaking 1

Associated Symptoms

• Ipsilateral ear or facial pain occurring around the time of onset 1
• Hyperacusis (increased sensitivity to sound on the affected side) indicating involvement proximal to the stapedius branch 1
• Altered or diminished taste on the anterior two-thirds of the tongue 1
• Dry eye and mouth due to autonomic fiber involvement 1

Physical Examination Approach

• Systematically test all facial movements: raising eyebrows, closing eyes tightly, smiling, puffing out cheeks 1
• Use the House-Brackmann grading scale (grades 1-6) to document severity, with grade 1 being normal and grade 6 being total paralysis 1, 2
• Perform complete cranial nerve examination—any additional cranial nerve deficit excludes Bell's palsy and mandates immediate imaging 1
• Assess eye closure carefully to determine risk of corneal exposure 1

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Immediate Management Algorithm

Step 1: Confirm Diagnosis and Exclude Red Flags

Do NOT order routine laboratory tests or imaging for typical presentations—this delays treatment beyond the critical 72-hour window without improving outcomes. 1, 3, 2

Red Flags Requiring MRI with Contrast (Not Bell's Palsy)

• Forehead sparing (suggests central stroke) 1
• Bilateral facial weakness 1, 2
• Isolated branch paralysis (only lower face affected) 1, 2
• Other cranial nerve involvement 1, 2
• Progressive weakness beyond 3 weeks 1
• Recurrent paralysis on the same side 1, 2

Step 2: Initiate Corticosteroid Therapy Within 72 Hours

Prescribe oral corticosteroids immediately for all patients ≥16 years presenting within 72 hours of symptom onset—this is the ONLY proven effective treatment and significantly improves complete recovery rates. 1, 3, 2

Evidence-Based Regimens (Choose One)

• Prednisolone 50 mg once daily for 10 days (no taper required) 1, 3, 2
• OR Prednisone 60 mg once daily for 5 days, followed by a 5-day taper 1, 3, 2

Clinical Efficacy Data

• 83% complete recovery at 3 months with prednisolone versus 64% with placebo (NNT = 6) 1
• 94% complete recovery at 9 months with prednisolone versus 82% with placebo (NNT = 8) 1
• No benefit exists if treatment starts beyond 72 hours 1, 3, 2

Step 3: Consider Antiviral Therapy (Optional, Minimal Benefit)

Never prescribe antiviral monotherapy—it is completely ineffective and delays appropriate corticosteroid treatment. 1, 3, 2

• Combination therapy (antiviral + corticosteroid) may be offered within 72 hours for severe cases, yielding a modest increase in recovery (96.5% vs 89.7% with steroids alone; absolute benefit +6.8%) 1
• Valacyclovir 1 g three times daily for 7 days OR acyclovir 400 mg five times daily for 10 days 1, 4
• The large BELLS trial (n=496) found no statistically significant advantage of adding acyclovir: 71.2% recovery with acyclovir vs 75.7% without (P=0.50) 1

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Mandatory Eye Protection (All Patients with Impaired Eye Closure)

Implement aggressive eye protection immediately to prevent permanent corneal damage—this is non-negotiable for all patients with incomplete eye closure. 1, 3, 2

Daytime Measures

• Lubricating ophthalmic drops every 1-2 hours while awake 1, 3, 2
• Sunglasses outdoors to protect against wind and foreign particles 1, 3, 2

Nighttime Measures

• Ophthalmic ointment at bedtime for sustained moisture retention 1, 3, 2
• Eye taping or patching with careful instruction on proper technique to avoid corneal abrasion 1, 3, 2
• Moisture chambers using polyethylene covers for severe cases 1

Urgent Ophthalmology Referral Triggers

• Severe impairment with complete inability to close the eye 1
• Eye pain, vision changes, redness, discharge, or foreign body sensation 1
• Signs of corneal exposure or damage 1

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Follow-Up and Referral Algorithm

Early Reassessment (1-2 Weeks)

• Monitor recovery progress and reinforce eye protection 2
• Identify early complications or new neurologic findings 2

Mandatory 3-Month Reassessment

Refer to a facial nerve specialist if facial recovery is incomplete at 3 months after symptom onset—approximately 30% of patients may have permanent facial weakness requiring reconstructive options. 1, 3, 2

Urgent Referral Triggers (At Any Time)

• New or worsening neurologic findings 1, 3, 2
• Development of ocular symptoms 1, 3, 2
• Progressive weakness beyond 3 weeks 1

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Special Populations

Children

• Better prognosis than adults with up to 90% spontaneous recovery 2, 4
• Corticosteroid benefit is inconclusive in pediatric patients—no high-quality pediatric-specific trials exist 1
• Consider prednisolone 1 mg/kg/day (max 50-60 mg) for 5 days followed by 5-day taper for severe or complete paralysis after shared decision-making with caregivers 1, 2

Pregnant Women

• Treat with oral corticosteroids within 72 hours using individualized risk-benefit assessment 1, 2
• Eye protection measures are essential and safe in pregnancy 1, 2
• Up to 90% complete recovery rate in pregnant women 4

Diabetic Patients

• Diabetes is NOT a contraindication to corticosteroids—the therapeutic benefit outweighs the risk of temporary hyperglycemia 1
• Monitor capillary blood glucose every 2-4 hours during the first few days of steroid therapy 1
• Proactively adjust diabetes medications: increase basal insulin and add or increase prandial insulin as needed 1

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Prognosis and Natural History

• 70-80% of patients recover spontaneously without treatment 5
• Patients with incomplete paralysis have up to 94% recovery rates 1, 2
• Patients with complete paralysis have approximately 70% complete recovery within 6 months 1, 2
• Most patients begin showing recovery within 2-3 weeks 1, 3
• Complete recovery typically occurs within 3-4 months 1
• 30% may experience permanent facial weakness with muscle contractures 1, 2

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Common Pitfalls to Avoid

• Delaying treatment beyond 72 hours eliminates the effectiveness of corticosteroid therapy 1, 3, 2
• Prescribing antiviral monotherapy is completely ineffective and delays appropriate treatment 1, 3, 2
• Ordering routine labs or imaging for typical presentations increases costs without benefit and delays treatment 1, 3, 2
• Inadequate eye protection monitoring can lead to permanent corneal damage 1, 3, 2
• Failing to refer at 3 months delays access to reconstructive options and psychological support 1, 3, 2
• Missing atypical features (bilateral weakness, forehead sparing, other cranial nerve involvement) suggests alternative diagnoses requiring different management 1, 3, 2
• Improper eye taping technique can cause corneal abrasion—patients must be carefully instructed 1

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Therapies NOT Recommended

• Physical therapy: no proven benefit over spontaneous recovery 1, 2
• Acupuncture: poor-quality trials with indeterminate benefit-harm ratio 1, 2
• Surgical decompression: rarely indicated except in specialized centers for highly selected cases 1, 2
• Electrodiagnostic testing: NOT recommended for incomplete paralysis; may be offered only for complete paralysis 1, 2